Recently two techniques using free solution electrophoresis to separate charged-uncharged polymer conjugates have proven successful: End Labeled Free Solution Electrophoresis (ELFSE) for DNA sequencing, and Free Solution Conjugate Electrophoresis (FSCE) for molar mass profiling of uncharged polymers. Previous attempts have been made to analyze experimental data generated by these new techniques for the electrophoresis of molecules with varying charge distributions. However, the importance of the ends of the polymers in determining the polymer's overall mobility was neglected in previous work. Through a careful investigation and a reanalysis of the experimental data, it is determined here that this “end effect” critically impacts the behavior of polymers and charged-uncharged polymer conjugates during electrophoresis. In this way, the invention provides for methods that exploit this “end effect” for the separation of polymeric molecules on the basis of size, including for example DNA separation and sequencing techniques.